johnson



4 Sheets-Sheet 1.

(No Model.)

M. O. JOHNSON.

TWIST DRILL MILLING MACHINE.

Patented 001:. 23, 1888..

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(No Model.)

M. 0. JOHNSON.

TWIST DRILL MILLING MACHINE- Patented Oct.. 23, 1888.

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0; JOHNSON.

TWIST'DBILL MILLING MACHINE.

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(No Model.) 4 Sheets-Sheet 4. M. G. JOHNSON.

TWIST DRILL MILLING MACHINE.

N0. 391,6I9. Patented Oct. 23, 1888.

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NiTEn STATEs PATENT Unmet,

MOSES O. JOHNSON, OF HARTFORD, CONNECTICUT, ASSIGNOR TO AMOS WHITNEY AND CHARLES L. BARROXVS, OF SAME PLACE.

TWEST DRlLL MiLLING MACl'ilNE.

SPECIFICATION forming part of Letters Patent No. 391,619, dated October 23, 1888.

Application filed August 3.1888. Serial No. 281.879 (No model.) Patented in England April 24, 1888, No. 6,084; in Belgium April 24, 1888, No. 81,543; in France April 24, 1888,No. 190,204, and in Canada May 17, 1888, No. 29,175.

.To aZZ whom, it may concern:

Be it known that 1, Moses 0. JOHNSON, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Twist-Drill-Milling Machines, (for which I have obtained a patent in the following countries, to wit: Canada, May 17, 1888, No. 29,175; Great Britain, April 24, 1888, N 0. 6,084; Belgium, April 21, 1888, No. 81,513; France, April 24, 1888, No. 190,204,) of which the following is a specification,

This improved machine cuts the spiral grooves of twist-drills to have an increasing pitch and of decreasing depth,measuring from the point of the drill toward the shank thereof.

In the drawings accompanying and forming a part of this specification, Figure 1 is a plan of a twist-drill-milling machine embodying my invention. Fig. 2 isa front elevation of the machine,one of the milling-heads being removed. Fig. 3 is a horizontal vertical sectional elevation illustrating more in detail the arrange ment of the several parts. Fig. 4. is an elevation of that end of the machine which is at the right hand in Figs. 1, 2, and 3. Fig. 5 is a sectional elevation in line a a, Fig. 2. Fig. 6 is a horizontal section through one of the milling-heads. Fig. 7 is a detail drawing in two views of the drill-guide.

Similar characters designate like parts in all the figures.

The mechanisms of the machine are sup ported on and by some suitable bed, A,which may be set on pillars or otherwise sustained in usual manner. They consist of two millingheads, B B, oppositely disposed on one end of the bed; a drill-guide, 0, set between said heads B 13; the blanlecarrying spindle D,carried (directly or indirectly) in bearings; feed apparatus for simultaneously revolving and sliding said spindle D; a pattern apparatus for modifying the movement of said spindle to produce the desired increase of twist in the drill-grooves, and cams or patterns actuated and connected with the millingheads to govern the depth throughout their length of the drill-grooves.

The bed A is shown to be of the form of a fiat table provided with bearings for theshafts supported thereon and fitted to have the several removable parts of the machine attached thereto. On the front or left-hand end of this bed the two milling-heads are set in opposite and corresponding positions. As the said heads are duplicates except as to arrangement, their several corresponding details are designated by the same characters in each. A frame, F, has a base, 2, whereby it is bolted to the bed A by screws 3, and has an upright part, 4., which is fitted to receive the vertical ly-movable slide S. This slide is provided with two bearings, 5 being a clamp-bearing for the adjustable bearing L of the millingspindle P, and 6 an ordinary bearing for the hub 7 of the drivingwheel 8. In one milling-head these hearings are below and in the other above the plane of the drill-blank. The milling-spindle is fitted to carry the millingcutter T, has collar-nuts 9 for adjusting in usual manner its position in said slide/bearing L, and is splined into the driving-wheel, to be driven therefrom in usual manner. Collar-nuts 10 on wheel-hub 7 serve to hold the wheel 8 in proper longitudinal position. As shown in the drawings, and preferably, the wheel 8 is a gear driven by the pinion 8 on the hub of pulley N, which is carried on a stud, 8", that is fixed in slide S. The gears 8 8being bevel-gears, permit the pulleys to be so placed as to be more readily belted to one ordinary driving-shaft, which is not shown.

The vertical adjustment of themilling-slidcs S is effected by means of the adj usting-screw 12, properly squared at 11, which screw turns in the slide S and is tapped into the spindle 50, which spindle is fitted to slide in said slide S, that passes down through the table and rests with its lower end, 18, on certain cams that will be hereinafter described.

The drill-blank guide 0 consists of bracket 16, suitably placed and secured to the bed A, and a bushing or thimble, 15, removably fixed in said bracket and perforated at 17 18 for 9 the upper and lower millii'ig-cutters, respectively. One of the bushings is provided for each diameter of drill which is to be grooved by the machine.

The spindle I) is to be fitted with some suit- IOO able means, as chuck 19 or other well-known device,forholding the drill-blank 20, and is to be supported in axial alignment with the aforesaid bushing of the drill-guide C. One end of said spindle (the right-hand end in this instance) hasa thread, 21, which engages with a corresponding internal thread in the hub 23 of the gear 24, which gear is supported by said hub in the bearing 25 on bed A. The gear 24 is (or may be) a worm-gear, being driven by the Worm 27 on driving-shaft 28, which shaft is carried in bearings 30, and is itself driven by a pulley. 31. A hand-wheel, H, on shaft 28 is provided for operating the feed mechanism by hand. By these means a longitudinal movement is imparted to said blank-carrying spindle. The opposite end of spindle D has a spline, 32, and is fitted to slide through (but not to turn within) the hub 33 of the worm-gear 34, which gear is carried by its said hub in bearing 35 on bed A. The usual nut or collar, 37, is provided to hold said gear in place insaid bearing. A worm, 36, carried by shaft meshes with said gear 34, and is driven by means of connectingshafts and gearing from the gear 42 on the aforesaid hub 23 of gear 24. The shaft 40 extends through the hub 41 of the bevel-gear 43, (carried in bearing 51,) and is splined thereto in usual manner. Gear 43 meshes with gear 44 on shaft 45, which is provided at the opposite end with the change-wheel 46, that is connected by intermediate Wheel, 47, with the aforesaid driving-gear 42. Shaft 45 is carried in bearings 48 49, and by means of the changegearing 42 46 47 may be driven at any required speed relative to the feed-nut (or hub) 23. The intermediate change-gear, 47 is carried in usual manner by the stud 53, which is adj ustably fixed in the adj ustably-fixed arm 54.

For producing the required increase of pitch in the drill-grooves, I employ a cam, M, having a pattern-groove, 60., formed therein of suitable character for the required purpose. Said cam M is carried on the shaft 61, which turns in bearings 62 63 on bed A. This shaft 61 is about parallel to shaft 40 and has a wormgear, 65, whereby the same is driven from worm 66 on shaft 45. By this means cam M has a simultaneous and normally-corresponding rotary movement relative to spindle D.

The forward end of shaft 40 is carried in a slide or sliding bearing, 70, (being held therein by nuts 69,) which is fitted to slide in the bearing 68. Said slide has an arm, 72, which reaches out through the guide-slot 71 in said bearing and enters the groove in cam M. As the cam revolves, the slide is thus moved endwise, carrying with it the worm 36, which then acts as a rack to revolve spindle D. This auxiliary movement modifies the normal movement imparted to said spindle by the gearing hereinbefore described, such modification being governed by the shape of said cam-groove 60.. It is contemplated to use different cams M as the drills to be grooved may require.

The vertical adjustment of the cutters T and the means therefor have already been described; but the slides 8 have also a working movement for the purpose of governing the depth of the drill-groove throughout the different parts of its length. For this purpose the spindles 50 50 pass downward and rest on cams 80 80, respectively, which cams are removably fixed on a shaft, 82, that is carried in bearings underneath said slides S. Shaft 82 has a gear, 81, meshing with gear 83 on shaft 84, and this latter shaft has a spiraltoothed gear, 85, meshing with the similar gear, 86, on shaft 61. By this means the cams 80 move in unison with cam M and spindle D. The slides S are moved downby stout springs 88-on pull-rods 90, that are attached to said slides. The cams 80 are made of such external conformation as required for producing the desired variation in the depth of the camgrooves, and they are set on their shaft one oppositely to the other, so that when one slide (carrying the cutter above the drill) goes up the other slide will go down.

The operation of my machine is as follows: The milling-cutters being properly driven,the drill-blank 20 is secured in the chuck of spindle D,which is fed forward by hand until the point of the blank enters the bushing 15, ready to begin milling. The shaft 28 is now set rotating in proper direction by a belt on pulley 31 from a counter-shaft. (Not shown.) This imparts motion to the several shafts and wheels, as shown by arrows thereon, and gives to spindle D rotating and advancing motions, of which the former is modified as required by the cam M. At the same time the cams 80 separate the cutters to give the proper variation in the depth of the two opposite spiral drill-grooves. The drill being milled for a sufficient distance, the shaft 28 is stopped and the spindle D then retracted by hand, the drill is removed, and the several operations repeated as before.

This machine is capable of modification in various ways and degrees, after the manner of machines in general, within the scope and limits of my invention.

Having thus described my invention, I elaim 1. The combination of the splined and threaded spindle D, the feed-nut engaging the thread on said spindle, the worm-gear splined to said spindle, a worm meshing with said Worm-gear, the cam M, connecting shafts and gearing simultaneously rotating said worm and the feed-nut and cam M, said cam being operatively connected to slide said worm during the rotary movement thereof, substantially as described.

2. The combination of the spindle D, the driving-wheel 34, splined thereto, worm 36 IIO on shaft 40, slide 70, and the cam geared to revolve in unison with shaft 40, the slide being connected to be actuated from said cam, all substantially as described.

3. The combination, in a twist-drill-milling machine, of the spindle D, the increase-pitch feed-apparatus,substantially as described, the oppositely-disposed milling-heads, and liftingcams operating the slides of said heads, said lifting-cams being geared to move in unison with the pattern-cam of said apparatus, all substantially as described.

4. The combination, in a machine of the class specified, of the slide S, cam 80, and spindle 50, bearing on said cam and adj ustably fixed in said slide, all substantially as shown and described.

5. The combination, with spindle D and with shafts 40 and 61, geared together, as described, ofgear 34,sp1ined to said spindle, worm 36 on shaft 40, the pattern-cam, bearing 68, having slot 71, and slide 70, having arm 72,

MOSES c. 'JoHNsoN.

Witnesses:

FRANCIS H. RICHARDS, WILBUR M. STONE. 

